The present invention relates to a glycoprotein. More particularly, it relates to a pharmaceutically-active glycoprotein, having a molecular weight of 38 kD, which can be obtained in substantially pure form from an extract of the grain of Avena sativa (oat). The invention also relates to a process for the preparation of such an active glycoprotein and to an immunomodulating pharmaceutical composition containing the glycoprotein as an active ingredient, which composition is useful in the prevention and treatment of viral and bacterial infections.
Glycoprotein fractions from the bacterium Klebsiella pneumoniae, having molecular weights ranging from 95 to 350 kilodaltons (kD), have been used to treat patients suffering from chronic bronchitis. Administration of 2 to 8 mg of these glycoprotein extracts improved the antimicrobial activity of monocytes in these patients, and appeared to prevent superinfection.
Bacteria possess several disadvantages as a source of pharmaceutically-active proteins. In particular, purification of proteins from a fermentation medium must be rigorous, in order to prevent the possibility of side effects from substances in the medium, for example, lipopolysaccharides. Isolation of a protein from plant tissue reduces the risks of side effects, and generally provides a more inexpensive source material.